AT&T Worldnet problems - but unlike the posted bugs, I get connected ok. Performance thereafter is just unusably poor. Doesn't seem to be hardware or line problems - Windows 98 on the same machine works fine.
This is a bug on the worldnet side, I understand. Try to fix it in the short term with echo 'PPPOPTIONS=noccp' >> /etc/sysconfig/network-scripts/ifcfg-ppp0 If that doesn't fix it, reopen this bug with full information about your serial setup (ports, config files with phone numbers, login names, and passwords elided, etc.)